shell/env: use XDG_RUNTIME_DIR for TMP/TEMP/TEMPDIR if available

diff --git a/shell/env b/shell/env
index bd529ba1ce2f5ef25542d3d7a48f9e9394062add..fa7e6da69fb5fd5ce2dc1eafc2cbc87423445bcf 100644 (file)
--- a/shell/env
+++ b/shell/env
@@ -80,16 +80,19 @@ LESS_TERMCAP_so="${escape}[01;30;43m"
 LESS_TERMCAP_se="${escape}[0m"
 export LESS_TERMCAP_so LESS_TERMCAP_se
 
-# Use ~/.tmp as directory for temporary files if available to reduce security
-# problems on multi-user systems.
-if test -d "$HOME/.tmp"; then
+# Prefer a private and most likely fast directory (tmpfs) for temporary files
+# to reduce security problems on multi-user systems.
+if test -n "$XDG_RUNTIME_DIR" && test -d "$XDG_RUNTIME_DIR"; then
+    TMP="$XDG_RUNTIME_DIR"
+# Use ~/.tmp and ~/.tmp as fallback.
+elif test -d "$HOME/.tmp"; then
     TMP="$HOME/.tmp"
-    TEMP="$TMP"
-    TMPDIR="$TMP"
-    export TMP TEMP TMPDIR
-# Also try ~/tmp as fallback.
 elif test -d "$HOME/tmp"; then
     TMP="$HOME/tmp"
+else
+    TMP=
+fi
+if test -n "$TMP"; then
     TEMP="$TMP"
     TMPDIR="$TMP"
     export TMP TEMP TMPDIR